1. Field of the Invention
The present invention generally relates to log peeling apparatus and, more particularly, is concerned with a portable log peeling apparatus having a draw knife and designed to provide a hand hewn finish to a log peeled with the apparatus.
2. Description of the Prior Art
In recent years there has been a substantial increase in the construction of log cabins and homes in mountain areas. The demand for the log homes is a result of their beauty, longevity and natural insulation properties. The latter is especially important in freezing and subfreezing mountain weather. The construction of a log home is a demanding task, due to the raw state of the construction materials. The first steps in building a log home are to select and dry the logs and then to peel the bark off the logs. If a hand hewn look to a log home is desired, then it is necessary to peel the bark off the logs in a manner that results in a relatively smooth surface along the natural contour of the log. A method of peeling a log that would leave gouges or grooves in the log would substantially detract from the beauty of a log home. The desire to reduce the amount of labor required to properly peel the logs has created the need for a powered log peeling apparatus.
Currently hand hewn logs are attained by manually peeling logs with a draw knife. A draw knife is designed with a handle on each end of a blade with a bevel on one edge. A person operates a manual draw knife by straddling a felled log, placing the draw knife on the log with the bevel on the blade facing the log, and then dragging the draw knife along the log. The blade of the draw knife cuts through the bark and cambium layers of wood. The dragging action pulls the draw knife blade along the top of the hard layers of wood leaving them intact. The result is a relatively smooth peeled surface along the contour of the log. This method of attaining a hand hewn log is very labor intensive, too time consuming, and not economical.
Other methods of peeling logs are described in U.S. Pat. Nos. 1,937,073, 2,672,899, 2,676,628, 2,705,982, 2,802,497, and 3,037,537 issued to Stove, Kafka, Hastain, Ponts, Yeadon, and Romer, respectively. The Stove patent describes a disbarking machine that operates by mounting disbarking tools on a chain that travels across the trunk on guide means riding on the trunk. While the Stove invention speeds the peeling of a log, it results in grooves around the peeled log and an appearance that is unacceptable for a log home.
The Kafka invention describes the use of a prime mover to drive an eccentric, which in turn causes a reciprocation of a blade assembly slidably mounted on a frame. The disadvantage of the Kafka design is that it does not result in a hand hewn effect for the peeled log. Another disadvantage of the Kafka design is the rigid manner in which the blade is mounted in the frame, which results in little flexibility in peeling an uneven log.
The Hastain invention uses a chain saw motor and an eccentric to reciprocate a chisel type cutting tool. The disadvantage of this design is that the use of a chisel results in unacceptable grooves on a peeled log.
The Ponts invention uses a pneumatic hammer to reciprocate a chisel. This invention has the same disadvantage as the Hastain design.
The Yeadon invention is quite complex and is not designed to achieve a hand hewn appearance for a peeled log. Furthermore the Yeadon design is not portable.
The Romer invention uses a steel band driven in a reciprocating movement. The reciprocating movement is provided by either a electric motor or an internal combustion engine and is counterbalanced to minimize vibration. The steel band is mounted in a double arm such that one end of the steel band is movably mounted so that it can be adjusted longitudinally during operation to the shape of the log being peeled. A disadvantage of Romer is the constant reciprocating motion caused by the use of a motor, which does not give the operator control of each stroke of the peeling tool. This can result in a ragged peeling of the log. Another disadvantage is that the steel blade is effectively pushed rather than pulled in the manner of a draw knife. This can result in the steel band digging into the log instead of drawing along the cambium layer as a draw knife does. Also as described in the Romer patent the steel band is provided with a bevel on its leading top edge, while a draw knife has the bevel on its leading bottom edge. The latter difference is a key reason why a draw knife provides a smooth hand hewn appearance, while other disbarking tools result in a less satisfactory appearance.
Due to the unsatisfactory operation and appearance of the logs peeled using the prior state of art log peelers, a need exists for a new design for a log peeler which will be portable, provide a hand hewn appearance for a peeled log, and be easy to operate.